4.6 Article

Herbig-Haro flows in B335

期刊

ASTRONOMY & ASTROPHYSICS
卷 475, 期 1, 页码 281-300

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EDP SCIENCES S A
DOI: 10.1051/0004-6361:20077889

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ISM : jets and outflows; infrared : ISM; ISM : lines and bands; stars : formation; ISM : individual objects : B335; ISM : individual objects : HH119

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Aims. To study the Herbig-Haro flows in the nearby dark globule B335. To find new HH objects and H-2 knots, make a proper motion map of the flow activity and investigate physical properties through shock models. Methods. We have observed optical ( H alpha and [SII]) and near-IR (2.12 mu m H2) deep fields and taken optical spectra using the 2.56 m Nordic Optical Telescope, as well as a near-UV deep field ( U band) using the 3.58 m NTT. In addition we present new SPITZER/IRAC ( 3.5-8.0 mu m) and MIPS ( 24 mu m) observations. We use previous Ha and 2.12 mu m H2 observations taken 15 and 9 years earlier to make proper motion maps. We then investigate the shock physics by matching our spectra with planar shock models. Results. We discover five new HH objects ( HH 119 D-H) in the eastern and one (HH119 I) in the western lobe of the outflow. From proper motions we find an optically bright, roughly E-W oriented group with high space velocities ( 200-280 km s(-1)) and a near-IR bright, slower group ( 15-75 km s-1) moving to the ESE. We also find a system of at least 15 H2 knots in the western lobe. This (WNW) counterflow suggests the possibility of a binary outflow source, giving rise to two outflow axes with slightly different orientations. We find that the E-W flow is symmetrical with evidence for two outbursts. We make the first detection of [OI] lambda lambda 6300/63 in HH119 B and H beta in HH119 A and B and find their extinctions to be AV approximate to 1.4 and 4.4, respectively. HH 119 A is found to expand much faster than expected from linear expansion with distance from the outflow source. Using planar shock models we find shock velocities of -60 km s-1 ( A) and -35 km s-1 ( B and C). This agrees with A being of higher excitation than B and C. In our U image we detect three of the HH objects and propose that the emission arise from the [OII]lambda 3728 line and the blue continuum. New SPITZER/IRAC and MIPS observations show most of the HH objects at 4.5 mu m and a E-W elongated hour-glass shaped structure at the outflow source. Even at 24 mu m it is not clear whether most of the light is direct or reflected.

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